BRPI1005981B1 - aqueous silanized dispersion, process for producing an aqueous dispersion of signaled colloidal silica particles, aqueous dispersion and use of a dispersion - Google Patents

Description

(54) Title: WATER SILANIZED DISPERSION, PROCESS OF PRODUCTION OF A WATERED DISPERSION OF SIGNED COLOIDAL SILICA PARTICLES, WATER DISPERSION AND USE OF A DISPERSION (73) Holder: AKZO NOBEL CHEMICALS INTERNATIONAL BV. Address: Stationsstraat 77, NL-38 MH Amersfoort NL - Netherlands, NETHERLANDS (NL) (72) Inventor: PETER HARRY JOHAN GREENWOOD; HANS LAGNEMO; MARTIN LAGNEMO.

Validity Period: 20 (twenty) years counted from 03/10/2010, observing the legal conditions

Issued on: 11/21/2018

Digitally signed by:

Alexandre Gomes Ciancio

Substitute Director of Patents, Computer Programs and Topographies of Integrated Circuits

1/24

DISPERSION OF WATER SILANIZED SILICA, PROCESS OF PRODUCTION OF A WATER DISPERSION OF SILANIZED COLOIDAL SILICA PARTICLES, WATER DISPERSION AND USE OF A DISPERSION

The present invention relates to a process for providing an aqueous dispersion comprising silanized colloidal silica particles in which the silane groups originate from a) at least one silane compound containing epoxy functionality, b) at least one silane compound without epoxy functionality that is capable of modifying the colloidal silica particles that can be obtained by mixing silane compounds containing silane group precursors a) and b), and colloidal silica particles in any order to form the dispersion of silanized colloidal silica particles . The invention also relates to the use of silanized colloidal silica dispersion.

HISTORY OF THE INVENTION

Colloidal silica dispersions have previously been used, among other things, as a coating material to improve the adhesive properties and increase the wear and water resistance of various materials. However, these compositions, especially highly concentrated colloidal silica compositions, may be susceptible to gel formation or precipitation, which considerably reduces the storage time.

• - 25

EP 1554221 discloses a process for providing a dispersion of silane modified silica.

However, the stability of these dispersions may not always provide sufficient stability, hardness and / or water resistance.

It would be desirable to provide an improved silanized silica sol dispersion with respect to deficiencies above the prior art. It would also be desirable to provide a highly concentrated colloidal silica dispersion for, among other things, coating applications that can be easily

2/24 · - 25 stored and transported without any initial precipitation. Another objective is to provide a dispersion that gives high resistance to water and / or hardness, in particular early hardness, to varnish formulations. It would also be desirable to provide a convenient and economical process for producing this dispersion.

Another objective is to provide a suitable dispersion for wood varnishes that do not discolor wood, for example, oak. It is another objective of the invention to provide improved water resistance to wood varnish formulations.

THE INVENTION

The present invention relates to a process for producing an aqueous dispersion of silanized colloidal silica particles comprising mixing in an aqueous medium of a) at least one silane compound containing an epoxy functionality, b) at least one silane compound without epoxy functionality that is capable of modifying colloidal silica particles; and c) colloidal silica particles in any order to form an aqueous dispersion of silanized colloidal silica particles containing silane groups originating from a) and b).

According to one embodiment, the silanized colloidal silica particles are capable of imparting varnish hardness and / or water resistance.

According to one embodiment, b) is selected from silanes with starch functionality, ureido functionality, amino functionality, ester functionality, mercapto functionality and / or isocyanate functionality, for example, from silanes with starch functionality, ureido functionality and / or functionality amino, for example, starch and / or a ureido functionality.

According to one embodiment, the weight ratio between

3/24

b) and a) varies from approximately 2 to approximately 0.1, for example, from approximately 1.5 to approximately 0.2, or from approximately 1.1 to approximately 0.4.

According to one embodiment, the weight ratio of both a) and b) to silica ranges from approximately 0.01 to approximately 3, for example, approximately 0.01 to approximately 1.5, for example, approximately 0.05 up until

about 1, or in about 0.10 up until about 0.5, or in about 0.2 up until 10 approximately 0.5, or in about 0.3 up until

approximately 0.5.

According to one embodiment, the starch functionality comprises (meth) acrylamide groups. According to one embodiment, the silane with starch functionality includes, for example, monomers containing ethylenically unsaturated silane from met (acrylamides) containing silane groups of the general formula (II) CH ₂ = CR ⁵ -CO-NR ⁶ -R ⁷ -SiR ⁸ _m - (R ⁹ ) 3-m, where m = 0 to 2, R ⁵ is both H and a methyl group, R ^s is H or an alkyl group having 1 to 5 carbon atoms; R ⁷ is an alkylene group having 1 to 5 carbon atoms or a divalent organic group in which the carbon chain is interrupted by an O or N atom, R ⁸ is an alkyl group having 1 to 5 carbon atoms, and R ⁹ is an alkoxy group having 1 to 40 carbon atoms, which can be replaced by other heterocycles. In monomers in which two or more R ⁵ or R ⁹ groups occur, these groups can be identical or different. Examples of (meth) acrylamido-alkylsilanes of this type are 3 - (meth) acrylamido-propyltrimethoxysilanes, 3- (meth) acrylamido-propyltriethoxysilanes, propyltri (β-methoxyethoxy) silanes, methylpropyltrimethoxylsilanes, methylethyltrimethoxysilanes, ethylethoxyethylsiloxypropyl

3- (met) acrylamido2- (met) acrylamido-22- (met) acrylamido-2N- (2- (met) acrylamido3- (met) acrylamido2- (met) acrylamido-ethyltri4 / 24 methoxysilanes, 1- (meth) acrylamido -methyltrimethoxy-silanes, 3 (meth) acrylamido-propylmethyldimethoxy-silanes, 3 (met) acrylamido-propyldimethylmethoxy-silanes, 3- (N-methyl (meth) acrylamido) -propyltrimethoxysilanes, 3 - ((meth) acrylamidomethoxy) -3- hydroxy-propyltrimethoxysilanes, 3 - ((meth) acrylamido-methoxy) -propyltrimethoxysilanes, N, Ndimethyl-N-trimethoxy-silylpropyl-3- (meth) acrylamidopropylammonium chloride and N, N-dimethyl-N-trimethoxyethylpropyl2- (methyl ) acrylamido-2-methylpropylammonium.

According to one embodiment, the silane with ureido functionality includes, for example, β-ureidoethyltrimethoxysilane, β-ureidoethyltriethoxysilane, γureidoethyltrimethoxysilane and / or γ-ureidopropyltriethoxysilane.

According to one embodiment, the silane with ureid functionality can have the structure Β ₍₄ _ _η ) -Si- (AN (H) C (O) -NH ₂ ) _n , where A is an alkylene group containing from 1 to approximately 8 carbon atoms, B is a hydroxyl or alkoxy group containing from 1 to approximately 8 carbon atoms, and an integer from 1 to 3, provided that if n is 1 or 2, each B can be the same or different.

According to an embodiment, the silane with epoxy functionality includes, for example, glycidoxy and / or a glycidoxypropyl group, for example, gamma-glycidoxypropyl trimethoxysilane, gamma-glycidoxypropyltriethoxysilane, methyldiethoxysilane gamma-glycidoxypropyl methyldiethoxysilane, (3-glycidoxypropyl) (3-glyoxypropyl) trimethoxysilane 3-glycidoxypropyl) hexyltrimethoxysilane, beta- (3,4-epoxycyclohexyl) ethyltriethoxysilane.

According to one embodiment, the silane with epoxy functionality includes at least one glycidoxy or glycidoxypropyl group, particularly gamma glycidoxypropyltrimethoxysilane and / or gamma glycidoxypropylmethyldiethoxysilane.

5/24

According to one embodiment, the mercapto-functional silane includes 3mercaptopropyltrimethoxysilane, HS (CH ₂ ) 3, Si (OCH ₃ ) ₃ , mercaptosilane having at least one hydroxyalkoxysilyl 5 group and / or a cyclic, gamma-mercaptopropyl trimethoxysilane group -mercaptopropyl triethoxysilane.

According to one embodiment, the silane with amino functionality is selected from aminomethyltriethoxysilane, Ν- (β10 aminoethyl) aminomethyltrimethoxysilane, aminomethylmethyldiethoxysilane, N- (βaminoethyl) methyltriethoxysilane, γ-aminopropyltrietoxisilane, γ-amino, γ-amino, γ-amino, γ-amino, γ-amino -γ15 aminopropyltrimethoxysilane, and N- (β-aminoethyl) -yaminopropylmethyldimethoxysilane. Other specific examples of the above silane functionalities that can be used include those mentioned in US 5,928,790, incorporated herein by reference.

According to one embodiment, the silane compounds can be mixed in any order with the colloidal silica particles. According to one embodiment, at least one silane compound with epoxy functionality is mixed with the colloidal silica particles before mixing it with at least one silane compound b).

According to one embodiment, the silane compound with epoxy functionality is mixed with the colloidal silica particles after the silica has been modified with the silane compound b), for example, the 30 amine functional silane.

According to one embodiment, the silane compounds a) and b) are mixed with colloidal silica particles at a pH below 12, for example, below 11,

6/24 below 10 or below 9.5. According to one embodiment, the mixing of silane compounds, for example, silane with amino functionality, is carried out at a pH above 10, for example, above 11.

According to one embodiment, the mixture of silane compounds and colloidal silica particles can be carried out at a pH of approximately 1 to approximately 13, for example, from approximately 6 to approximately 12, or from approximately 7.5 to approximately 11, or from approximately 9 to approximately 10.5.

The mixture of silane and colloidal silica particles can be carried out continuously, for example, at a temperature of approximately 20 to approximately 95, for example, from approximately 50 to approximately 75, or from approximately 60 to approximately 70 ° C. Silane is, for example, slowly added to the silica particles under vigorous stirring at a temperature of approximately 60 ° C and at a controlled rate, which varies suitably from approximately 0.01 to approximately 100, for example, approximately 0.1 up to approximately 10, approximately 0.5 to approximately 5, or approximately 1 to approximately 2 silane molecules per nm ² of colloidal silica surface area (in the colloidal silica particles) and hour. The addition of silane can be continued for any suitable time depending on the rate of addition, amount of silane to be added, and desired degree of silylation. However, the addition of silane can be continued up to approximately 5 hours, or up to approximately 2 hours until an appropriate amount of silane compounds a) and b) has been added. The amount of a) and b) added to the colloidal silica particles suitably ranges from approximately 0.1 to

7/24 approximately

6, for example, approximately approximately i continuous surfaces

3, or of approximately approximately silane molecules per nm ² of colloidal silica.

0.3 area even from silane particles to colloidal particles can be prepared when preparing highly concentrated silanized silica dispersions which is particularly important having a silica content of silica

0 to up to approximately 80% by weight, in the dispersion suitably ranges from approximately 80, from approximately 70, or approximately 60% by weight.

According to a

However, the content of approximately approximately 25 from approximately 30 to even silane compounds a) and b), from mixing with the water particles to form a premixed weight of approximately 1: 8 to approximately approximately stable silane-water and easy to mix a reason

8: 1,

1: 3,

OR

1: 1.5.

realization, at least one for example, a) is diluted before colloidal silica, that is, with silane and water, until

3: 1 up to

1.5: 1 to

The resulting solution is suitably approximately approximately approximately substantially transparent and with colloidal silica particles. In the continuous addition of silane to the colloidal silica particles, mixing can be continued from approximately 1 second to approximately 30 minutes, for example, from approximately 1 to approximately 10 minutes after the silane addition has been stopped.

According to one embodiment, the relative increase in dispersion viscosity two months after preparation is less than approximately 100%, for example, less than approximately 50%, or less than approximately 20%. According to one embodiment, the relative increase in dispersion viscosity four months after preparation is less than

8/24 approximately 200%, for example, less than approximately 100%, or less than approximately 40%.

Colloidal silica particles, also referred to herein as silica sol, can be derived from, for example, precipitated silica, micro silica (silica vapor), pyrogenic silica (vaporized silica) or silica gels with sufficient purity, and mixtures thereof; these can be silanized by the process described in W02004 / 035474. In general, silica sol can also be obtained from sodium silicate, as described, for example, in US 5,368,833.

The colloidal silica and silica sol particles according to the invention can be modified and can contain other elements, such as amines, aluminum and / or boron, which can be present in the particles and / or in the continuous phase. Boron modified silicas are described, for example, in US 2,630,410. The aluminum modified silica particles suitably have an A1 ₂ O _{3 content} of approximately 0.05 to approximately 3% by weight, for example, approximately 0.1 to approximately 2% by weight. The procedure for preparing an aluminum modified silica sol is further described, for example, in The Chemistry of Silica, by Iler, K. Ralph, pages 407

409, John Wiley & Sons (1979) and US 5,368,833.

The colloidal silica particles suitably have an average particle diameter ranging from approximately 2 to approximately purple and approximately purple and approximately colloidal have nm.

150 nm, nm, up to approximately approximately approximately nm, approximately approximately, or approximately

Suitably, the silica particles specific surface area 20 to approximately 1500, for example, 50 to approximately 900, 70 to approximately 600 m ² / g, or one of de

9/24 approximately 130 to approximately 360 m ² / g.

According to one embodiment, the colloidal silica particles can have a narrow particle size distribution, i.e., a low relative standard deviation of the particle size.

According to one embodiment, the relative standard deviation of the particle size distribution is the ratio between the standard deviation of the particle size distribution and the average particle size in numbers. The relative standard deviation of the particle size distribution is less than approximately 60% in numbers, for example, less than approximately 30% in numbers or less than approximately 15% in numbers.

Colloidal silica particles are suitably dispersed in an aqueous medium, suitably in the presence of stabilizing cations, such as K ⁺ , Na ⁺ , Li ⁺ , NH ₄ ⁺ , organic cations, primary, secondary, tertiary and quaternary amines, or mixtures of these in order to form an aqueous silica sol. However, dispersions also comprising organic medium, for example, lower alcohols, acetone or mixtures thereof, can be used, suitably in an amount of approximately 1 to approximately 20, from approximately 1 to approximately 10, or from approximately 1 to approximately 5% in volume of the volume of total dispersion medium. According to one embodiment, aqueous silicas without any other organic medium are used. According to one embodiment, the colloidal silica particles are negatively charged. Suitably, the silica content in the sol varies from approximately 20 to approximately 80, for example, from approximately 25 to approximately 70, and from approximately 30 to approximately 60% by weight. The higher the silica content, the more concentrated the colloidal silica dispersion

Resulting 10/24 silanized. The pH of the silica sol suitably varies from approximately 1 to approximately 13, from approximately 3.5 to 12, from approximately 6 to approximately 12, or from approximately 7.5 to approximately 11.

According to one embodiment, silica sol has an S value of approximately 20 to approximately 100, for example, approximately 30 to approximately 90, or from approximately 60 to approximately 90%.

It has been found that dispersions with an S value within these ranges can improve the stability of the resulting dispersion. The value of S characterizes the extent of aggregation of colloidal silica particles, that is, the degree of aggregate or microgel formation. The value of S was measured and calculated according to the formulas shown in J. Phys. Chem. 60 (1956), 955-957 by Iler, R.K. & Dalton, R.L.

The value of S depends on the silica content, viscosity and density of the colloidal silica particles. A high S value indicates a low microgel content. The value of S represents the amount of SiO2 in weight percent present in the dispersed phase of, for example, a silica sol. The degree of microgel can be controlled during the production process, as further described, for example, in US 5368833.

Silane compounds can form stable covalent bonds of siloxane (Si-O-Si) with silanol groups or be linked to silanol groups, for example, by hydrogen bonds, on the surface of colloidal silica particles.

According to one embodiment, the aqueous dispersion of the silanized colloidal silica particles is mixed with a varnish, for example, a water / base based varnish

11/24 water (or water miscible), for example, based on a resin, for example dispersions or emulsions of epoxy, polyurethane, acrylic, polyester, alkyd resins, for use in wood coatings, metal coatings, plastic coatings, paper coating or glass coatings and ceramic or mineral substrates.

In general, the term varnish includes any clear or colored varnish that dries off by solvent evaporation and generally by a curing process, as well as one that produces a hard and durable finish, at any level of gloss from ultra matte to high gloss and which can be further polished as needed.

According to one embodiment, an organic binder is added to the dispersion of the silanized colloidal silica particles. The term organic binder includes latex, water-soluble resins and polymers and mixtures thereof. Water-soluble resins and polymers can be of various types, for example, poly (vinyl) alcohols, modified poly (vinyl) alcohols, polycarboxylates, poly (ethylene glycol), poly (propylene glycol), polyvinylpyrrolidone, polyalylamine, poly (acrylic acid) ), polyamidamines, polyacrylamides, polypyrroles, proteins, such as casein, soy proteins, synthetic proteins, polysaccharides, such as cellulose derivatives including methylcelluloses, ethylcelluloses, hydroxyethylcelluloses, methylhydroxyethylcelluloses, ethylhydroxyethylcelluloses or carboxymethyl starches; chitosan, polysaccharide gums, such as guar gums, arabic gums, xanthan gums and mastic gums and mixtures or hybrids thereof. The term latex includes synthetic and / or natural latex based on emulsions of resins and / or polymers of various types, for example, styrene-butadiene polymers, butadiene polymers,

12/24 polyisoprene polymers, butyl polymers, nitrile polymers, vinylacetate homopolymers, acrylic polymers, such as vinylicacrylic copolymers or styrene acrylic polymers, polyurethanes, epoxy polymers, cellulosic polymers; for example, micro cellulose, melamine resins, neoprene polymers, phenol-based polymers, polyamide polymers, polyester polymers, polyether polymers, polyolefin polymers, polyvinyl butyral polymers, silicones, such as silicone rubbers and 10 silicone polymers (eg silicone oils),

polymers in urea-formaldehyde, polymers vinyl or mix or hybrids of these. In wake up with one realization, the dispersion in particles in silica colloidal silanized is mixed with one

varnish, for example, varnish suspended in water, for example, varnish for wood or epoxy, in a weight ratio between silica and varnish on an anhydrous basis of approximately 0.01 to approximately 4, for example, approximately 0.1 to approximately 2, or from approximately 0.2 to 20 approximately 1, or from approximately 0.2 to approximately 0.5. Similarly, the silanized particles can be mixed with an organic binder in the same proportions. According to one embodiment, the silanized colloidal silica particles are mixed with or another component, for example, an organic binder or a varnish at a moderate temperature, suitably from approximately 15 to approximately 35 ° C, or from approximately 20 to approximately 30 ° Ç. According to one embodiment, the components are mixed from approximately 10 seconds to approximately 1 hour, or from approximately 1 minute to approximately 10 minutes.

The invention also relates to an aqueous dispersion

13/24 obtainable by the process as described here. In particular, the invention relates to an aqueous dispersion comprising silanized colloidal silica particles, wherein the silanized colloidal silica particles comprise silane groups of a) at least one silane compound containing an epoxy functionality, and b) at least one compound silane without epoxy functionality. According to one embodiment, said silanes are capable of modifying colloidal silica particles. Silane groups can originate from any silane compounds as disclosed herein.

The dispersion components have suitably technical characteristics as disclosed here in the process section.

The aqueous dispersion is capable of forming a coating film on various types of substrates.

According to one embodiment, the aqueous dispersion further comprises a varnish, for example, a varnish suspended in water. The aqueous dispersion is able to give better hardness, especially the early hardness and / or water resistance to a varnish formulation.

According to one embodiment, the dispersion has a silica content of approximately 1 to approximately 80, for example, approximately 10 to approximately 70, approximately 20 to approximately 50% by weight based on the anhydrous material in the dispersion. In addition to being more efficient in terms of stability, the dispersion has a shorter drying time after application on a material to be coated.

The energy used for drying can therefore be considerably reduced. A high silica content in the dispersion is preferred, as long as the silanized colloidal silica particles remain stably dispersed without any substantial aggregation, precipitation and / or

14/24 gel formation. This is also advantageous from the point of view of their lower transport costs.

According to one embodiment, the weight ratio of both a) and b) to silica in the dispersion ranges from approximately 0.01 to approximately 3, for example, approximately 0.01 to approximately 1.5, for example, approximately 0 , 05 to approximately 1, or from approximately 0.1 to

about 0.5, or in about 0.2 to about 0.5, or in about 0.3 to about 0.5. In a deal with an achievement, the reason for weight between b) and the) ranges from approximately 2 to about 0.1, for example, from approximately 1.5 to about 0.2, or in about 1.1 to about 0.4.

The silica content comprises silica in silanized modified silica particles and unmodified silica particles which can also be present in the prepared dispersion. The total silane content is based on all freely dispersed silane and on all joined or bonded silane groups.

According to one embodiment, the dispersion further contains an organic binder, for example, a latex, as further described here. The total solid content of the dispersion comprising the organic binder and the silanized colloidal silica particles suitably ranges from approximately 15 to approximately 80, for example, from approximately 25 to approximately 65, or from approximately 30 to approximately 50% by weight. The weight ratio between silica and organic binder on an anhydrous basis is suitably in the range of approximately 0.01 to approximately 4, for example, approximately 0.1 to approximately 2, or from approximately 0.2 to approximately 1.

15/24

According to one embodiment, the silanized colloidal silica particles and the organic binder are present as discrete particles in the dispersion.

The stability of the dispersion facilitates its handling and application in any use, since it allows storage and does not need to be prepared on site immediately before use. The prepared dispersion can then be easily used directly. The dispersion is also advantageous in that it does not involve dangerous amounts of toxic components. The aqueous dispersion may contain a water-miscible, organic medium. For example, a suitable water-miscible organic medium can be comprised in the aqueous dispersion in an amount of approximately 1 to approximately 20, for example, in an amount of approximately 1 to approximately 10, or from approximately 1 to approximately 5% by volume of the total volume of water and organic medium.

The dispersion may also contain, in addition to the silanized colloidal silica particles, at least to some extent, non-silanized colloidal silica particles depending on the size of the silica particles, the weight ratio between silane and silica, the type of silane compound , reaction conditions, etc. Suitably, at least approximately 40 of the colloidal silica particles are silanized (modified by silane), for example, at least approximately 65, or at least approximately 90, or at least approximately 99% by weight. The dispersion may also comprise, in addition to silane in the form of silane groups or silane derivatives bound or bonded to the surfaces of the silica particles, at least to some extent, unbound and freely dispersed silane compounds. Suitably, at least approximately 40, for example, at least approximately 60, at least approximately 75, at least

16/24 approximately 90, or at least approximately 95% by weight of the silane compounds are attached to or bonded to the surface of the silica particles.

The invention further relates to varnish formulations comprising silanized colloidal silica particles as described herein.

The invention also relates to the use of silanized colloidal silica dispersion in coating applications, such as in varnish formulations, for example, wood varnishes or epoxy varnishes, as additives to provide better water resistance, hardness, in particular early hardness , and stability. Also, the dispersions of the invention can impart improved adhesion and wear resistance. The dispersion of the invention can also provide polishability and improved flow properties. These types of dispersions can also offer better film properties in pigmented systems, such as inks.

The dispersion is also suitable for coating and impregnating interlaced and non-interlaced textile materials, bricks, photo paper, wood, metal surfaces, such as steel or aluminum, plastic films, such as polyester, PET, polyolefins, polyamide, polycarbonates, or polystyrenes; fabrics, leather, paper and paper-based materials, ceramics, stone, cement materials, bitumen, rigid fibers, straw, glass, porcelain, different plastics, glass fibers for, for example, antistatic and resistant to grease; as binders for non-woven, adhesives, adhesion promoters, laminating agents, sealants, hydrophobizing agents, as binders, for example, for cork or sawdust powder, asbestos, and rubber residue; as auxiliaries in textile printing and the paper industry; as

17/24 additives for polymers as sizing agents, for example, for glass fibers; and for finishing leather.

Once described, it will be evident that the invention can be varied in several ways. These variations should not be considered to be outside the core and scope of the present invention, and all such modifications, as would be apparent to those skilled in the art, should be included in the scope of the claims. Although the examples below offer more specific details of the reactions, the following general principles can be revealed here. The following examples will better illustrate how the described invention can be realized without limiting its scope.

All parts and percentages refer to parts and percentages by weight, unless otherwise stated.

Examples

The A-E silanes used below are available from Momentive in Switzerland.

THE: Silquest A-187 B: Silquest A-1524 Ç: Silquest A-1100 D: Silquest A-1130 AND: Silquest A-178

Hydrolysis of silane (epoxy-silane containing glycidoxy) (silane containing ureido) (silane containing amino) (silane containing amino) (silane containing acrylamide)

The silane compounds A-E were added to the water with adjusted pH under moderate stirring at room temperature, whereby transparent solutions were obtained after 60 to 120 minutes.

Table 1. Silanes used

Silano N- Silane content (% by weight) Amount of water (g) Amount of silane (g) pH of water for hydrolysis pH of prehydrated silane THE 50 100 100 7 7

18/24

B 50 100 100 2.6 4 Ç 50 100 100 7 11 D 50 100 100 7 11 AND 50 100 100 3 4

The silica sol Bindzil 30/360 used, available from Eka Chemicals AB, Sweden, is shown in Table 2 below:

Table 2. Silica sol used - without surface modification

Sun N- Silica sol ' Amount of Silica Sol (g) Silica content (% by weight) Particle size, (nm) Surface modification pH Al Bindzil® 30/360 5000 30 7 There is not 9-10

Table 3. Varnishes suspended in water used

Commercial name Varnish type Base material / binder in varnish Sadolin® Golvlack Stark (white) Epoxy 2-pack Epoxy resin, polyetherdiamine Sadolin® Parkettlack Helblank varnish for 1-pack wood Acrylic dispersion suspended in water / polyurethane

Preparation of silanized colloidal silica dispersions

Pre-hydrolyzed silane solutions A - E (see

Table 1) were added dropwise to the silica sol Al under good agitation at a rate of 600 g of solution per hour. Stirring was continued for approximately 30 minutes after adding the silane.

The process temperature was 60 to 70 ° C. Pre-mixed samples of silane compounds diluted in water were prepared by mixing water and silane in equal amounts (see Tables 4-6). The mixtures were slowly stirred until clear solutions were obtained. The dilutions of silane were then mixed with silica sol with moderate stirring, unless otherwise indicated.

19/24 otherwise. Approximately 300 ppm of epoxy-free silane did not react with the silica particles.

Table 4. Silica are modified with epoxy-silane

Modified sun N ² Silica sol Amount of silica sol (g) Amount of prehydrolyzed silane, solution A, Table 1, (g) Silica content (% by weight) Particle size, (nm) PH BI Al 5000 600 30 7 7 * B2 Al 5000 600 27 7 10 B3 Al 5000 300 28 7 10

* pH reduced from 10 to 7 by cationic exchange of silylated silica.

Table 5. Dispersions of silanized colloidal silica treated with non-epoxy silane

N ² silanized sol silica Silica sol Silica sol (g) Prehydrolyzed silane solutions from Table 1 Weight of silane solution (g) Stable silanized sol silica 1 Al 5000 B 600 YEA 2 Al 5000 B 300 YEA 3 Al 5000 Ç 600 NOT 4 Al 5000 Ç 300 NOT 5 Al 5000 D 600 NOT 6 Al 5000 D 300 NOT 7 Al 5000 AND 400 YEA

Table 6. Dispersions of silanized colloidal silica treated with epoxy

N ² silanized sol silica Silica sol Silica sol (g) Silano Amount of pre-hydrolyzed silane (g) Stable silanized sol silica 8 BI 5000 - - YEA 9 B2 5000 - - YEA 10 BI 5000 B 600 YEA 11 BI 5000 B 300 YEA 12 B2 5000 Ç 600 YEA 13 B2 5000 D 600 YEA 14 B3 5000 D 300 YEA 15 * B2 5000 AND 360 YEA 16 * B2 5000 AND 400 YEA

*: pH reduced from 10.5 to 7.5 by cation exchange

20/24 of the silylated silica.

Table 7. Stability data for silane modified suns (No. 1-7 in Table 5) after one month

N- silanized sol silica pH Aim. (cP) Note 1 11.0 4.6 PH stable only 11, Gel formation ** 2 10.7 6.5 PH stable only 11, Gel formation ** 3 - - Not stable, gel formation 4 - - Not stable, gel formation 5 - - Not stable, gel formation 6 - - Not stable, gel formation 7 10.9 5.2 Not stable at low / neutral pH **

**: Gel formation occurs if the pH is reduced from 5 to 9 or less by either cation exchange or acid addition.

Table 8. Stability data for Suns No. 8-16 (in Table 6) after one month

Silanized sol silica N ° pH Aim. (cP) Note 8 7.0 6.8 Stable sun silica 9 10.9 6.7 Stable sun silica 10 8.1 11.7 Stable sun silica 11 8.1 5.1 Stable sun silica 12 11.5 4.5 Stable sun silica 13 11.4 3.8 Stable sun silica 14 11.4 4.3 Stable sun silica 15 * 8.3 4.0 Stable sun silica 16 * 8.1 3.5 Stable sun silica

*: pH reduced from 10.5 to 7.5 by cationic exchange 10 of the silylated silica.

The Kônig hardness test was performed after 1, 7, 14 and 30 days for formulations 1-6 and 7-11 of wood varnish and epoxy varnish, respectively.

Varnish formulations for wood (N ° 1-6):

21/24 g of silane-modified colloidal silica were added to 80 g of 1-pack water-based varnish under good agitation.

Wood coatings require a formulation with a neutral pH due to the discoloration of the oak that occurs if the pH exceeds 8.5. Therefore, it is necessary to have a silane modified silica sol that is stable at neutral pH and does not cause a pH shock in the coating formulation.

Epoxy varnish formulations (N ° 7-11):

g of silane modified silica sol were first added to 10 g of 2-pack epoxy varnish and then 10 g of epoxy hardener under good agitation.

The films were cast by a film applicator on glass plates. The thickness of the wet film was 200 pm and the hardness was measured after 1, 7, 14 and 30 days (drying and storage were carried out at room temperature).

The test was carried out with pendulum measuring equipment for Kõnig hardness according to the ISO 1522 standard (formerly ASTM D-4366).

Table 9. Varnish formulations for wood with / without the addition of sol modified by silane

Formulation N ² Varnish for wood Silica sol Soil silica (from Tables 5 and 6) 1 100 g - (reference) 2 80 g 20 g N ² 8 (reference) 3 80 g 20 g N ² 10 4 80 g 20 g N ² 11 5 80 g 20 g N ² 15 6 80 g 20 g N ² 16

Table 10. pH and viscosity of the varnish formulations (No. 1-6 in Table 9)

Formulation N ² pH Viscosity (cP, 20 C)

22/24

1 7.8 46 2 7.8 26 3 7.9 31 4 7.9 26 5 7.9 26 6 8.1 28

Table 11. Epoxy varnish formulations with / without silane modified silica sol

N ² Epoxy varnish Hardener Silica Sun Silica sol (from Tables 5 and 6) 7 10 g 10 g - (reference) 8 10 g 10 g 5 g (reference) 9 10 g 10 g 5 g N ² 12 10 10 g 10 g 5 g N ² 13 11 10 g 10 g s g N ² 14

All varnish formulations in Table 11 are stable in epoxy varnish for more than 2 months.

Table 12. Kõnig hardness (s) of the formulations according to Table 9

N ² 24 h 7 days 30 days Note 1 31 s 71 s 85 s Reference sample 2 52 s 98 s 110 s Sol silica modified only with epoxy-silane, reference 3 61 s 118 s 120 s Silica sol modified with epoxy silane and ureido silane 4 60 s 118 s 119 s Silica sol modified with epoxy silane and ureido silane 5 56 s 104 s 110 s Silica sol modified with epoxy silane and acrylamide silane 6 63 s 115 s 123 s Silica sol modified with epoxy silane and acrylamide silane

As can be seen in Table 12, formulations according to N— 3-6 based on doubly silanized colloidal silica dispersions demonstrate improved early hardness compared to the control sample (N ² 1) and mono colloidal silica dispersions -silanized (N ² 2). IS

It is of fundamental importance that the development of hardness is rapid, since users demand almost instantaneous use in applications such as placing furniture etc. on newly laid floors in which the varnish formulation for wood was used.

Table 13. Kónig hardness (seconds) of the formulations according to Table 11

N ² 24 h 30 days Note 7 27 s 180 s Reference sample 8 26 s 178 s Sol silica modified only with epoxy-silane (reference) 9 32 s 180 s Silica sol modified with epoxy silane and amino silane (Silquest A-1100) 10 36 s 191 s Silica sol modified with epoxy silane and amino silane (Silquest A-1130) 11 38 s 204 s Silica sol modified with epoxy silane and amino silane (Silquest A-1130)

It can be seen that formulations 9-11 based on double silanized colloidal silica dispersions 10 demonstrate improved early hardness compared to the control sample (N ² 7) and monosilanized colloidal silica dispersions (N ² 8).

Water resistance test (24 h)

Ten drops of water were placed on an old film of 24 h (20 ° C), as a substrate, with a transparent colloidal silica film. A 50 ml beaker was placed over the drops to protect them against evaporation. After 24 h, the plates were analyzed on a scale of 1-5.

The scale was; 1: Dissolved film

2: Partially dissolved

3: Impact on the film

4: Some impact on the film

5: No impact

Table 14. Water resistance (24 h) of the wood varnish formulations in Table 9

24/24

N- Water resistance Note 1 5 Reference sample 2 1 Sol silica modified only with epoxy-silane, reference 3 5 Silica sol modified with epoxy silane and ureido silane 4 5 Silica sol modified with epoxy silane and ureido silane 5 4 Silica sol modified with epoxy silane and acrylamide silane 6 4 Silica sol modified with epoxy silane and acrylamide silane

Table 15. Water resistance (24 h) of the epoxy varnish formulations in Table 11

N- Water resistance Note 7 4 Reference sample 8 4 Sol silica modified only with epoxy-silane, reference 9 4 Silica sol modified with epoxy silane and amino silane (Silquest A-1100) 10 4 Silica sol modified with epoxy silane and amino silane (Silquest A-1130) 11 4 Silica sol modified with epoxy silane and amino silane (Silquest A-1130)

Wood varnish formulations ^(Nos 1-6):

From the wood veneer formulations, it can be seen that significantly better water resistance is obtained for silane-modified silane particles with both ureido and acrylamide functionality; and epoxy-silane compared to epoxy.

Epoxy varnish formulations (7-11):

Water resistance is not negatively affected in any of the samples.

1/2

Claims (8)

1. PROCESS OF PRODUCTION OF AN Aqueous DISPERSION OF SILANIZED COLOIDAL SILICA PARTICLES, characterized by comprising the mixture in an aqueous medium of a) at least one silane compound containing an epoxy functionality, b) at least one silane compound without epoxy functionality able to modify colloidal silica particles; selected from silanes with starch functionality and silanes with ureid functionality; and c) colloidal silica particles in any order to form an aqueous dispersion of silanized colloidal silica particles containing silane compounds originating from a) and b), in which the weight ratio between a) and b) to silica ranges from 0.01 to 1.5. 2. PROCESS, according to claim 1, characterized in that the silanized colloidal particles are able in check hardness and / or resistance to water a varnishes ^. 3. PROCESS, according with any an of claims 1 to 2, featured in which reason in Weight between b) and the) It varies from 2 to 0.1. 4. PROCESS, according with any an of claims 1 to 3, characterized in that the aqueous dispersion is mixed with a varnish. Aqueous dispersion, characterized in that it is obtainable by the method of any one of claims 1 to 4. 6. Aqueous dispersion, characterized by comprising silanized colloidal silica particles, in which the silanized colloidal silica particles comprise silane groups originating from a) at least one silane compound containing an epoxy functionality and b) at least one silane compound without epoxy functionality , selected from silanes with starch functionality and silanes with functionality Petition 870180062456, of 7/19/2018, p. 9/12 2/2 ureido, in which the weight ratio between a) and b) and silica ranges from 0.01 to 1.5. 7. WATER DISPERSION, according to the claim 6, characterized in that the silanized colloidal silica particles are capable of giving a varnish better hardness and / or water resistance. Aqueous dispersion according to any one of claims 6 to 7, characterized in that the weight ratio between b) and a) varies from 2 to 0.1. Aqueous dispersion according to any one of claims 6 to 8, characterized in that the dispersion further comprises a varnish. 10. USE OF A DISPERSION, as defined in any one of claims 5 to 9, characterized in that it is in coating applications. Petition 870180062456, of 7/19/2018, p. 12/10